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Guillemette, S.

Publications and source records attributed to Guillemette, S..

2 recordsLinked to original sources

Human iPSC-derived prostate organoids with germline BRCA2 mutation undergo tumorigenic transformations

The lack of physiologically relevant in vitro prostate models has impeded studies of organ development and prostate tumorigenesis. We reprogrammed peripheral blood mononuclear cells (PBMCs) from individuals with and without pathogenic-germline BRCA2 mutation (MUT_BRCA2, CON_BRCA2) into induced pluripotent stem cells (iPSCs), which showed no differences in morphology, proliferation, or pluripotency markers. Differentiation of MUT_BRCA2 iPSCs into prostate organoids (iPROS) using defined growth factors and signaling molecules resulted in disrupted morphology, impaired polarity, increased proliferation, and elevated prostate-specific antigen (PSA) secretion compared to CON_BRCA2 iPROS. Transcriptomic profiling revealed early prostate cancer (PCa) signatures. Upon exposure to dietary carcinogens, MUT_BRCA2 iPROS showed further PSA elevation, enhanced proliferation, AMACR upregulation, p63 reducetion are markers of aggressive PCa. In vivo, MUT_BRCA2 iPROS formed tumors in immunodeficient mice. This patient-derived iPROS-platform recapitulates human-prostate mopphology and function, models early tumorigenesis events, and provides a valuable tool for studying PCa biology and enabling personalized drug discovery. IN BRIEFIn this study, we developed patients iPSC-derived prostate organoids (iPROS) with or without a pathogenic BRCA2 germline mutation that display human-prostate like morphology and function. MUT_BRCA2 iPROS displayed disrupted morphology, early tumorigenic changes, and formed tumors in mice. Upon carcinogen exposure, they showed markers of aggressive prostate cancer. This platform models early prostate tumorigenesis and enables personalized studies of cancer initiation and therapeutic response.

cancer biology↗

Down-regulation of Drosophila Glutactin, a cholinesterase-like adhesion molecule of the basement membrane, impairs development, compromises adult function and shortens lifespan

Basement membranes (BM) play fundamental roles in morphogenesis and tissue maintenance in multicellular organisms. Glutactin is a BM protein that belongs to the Cholinesterase-Like Adhesion Molecules (CLAMs) protein family. In Drosophila embryos, Glutactin has been shown to outline internal organs and to play a role in synapse formation. Here, we report that Glutactin is broadly expressed in BM surrounding most vital tissues of the larva and the adult, and within the larval muscle sarcomere. Ubiquitous RNAi driven down-regulation of Glutactin expression (Tub>Glt-RNAi) resulted in pronounced impairments in larval and adult locomotor behavior, reduced oviposition, and shortened lifespan. Muscle-specific down-regulation of Glutactin resulted in reduced larval crawling speed indicating a secondary function for Glutactin independent of BM expression. Tub>Glt-RNAi pupa showed abdominal scars, suggestive of defects in histoblast nest expansion and replacement of larval epidermal cells, and a high mortality rate at eclosion. Surviving adults showed a range of morphological and physiological defects including excess melanization and pigmentation, incomplete rotation and duplication of the genitalia, and abnormal heart morphology and contraction. Insofar excess melanization is symptomatic of internal tissue damage, we propose that Glutactin is essential for the mechanical stabilization of the BM and for its ability to withstand internal stresses.

developmental biology↗